This invention relates to the manufacture of ammunition, and specifically to the inspection of the level of propellant powder which has been metered into empty ammunition casings.
The invention is particularly applicable to an otherwise-conventional process of loading and assembling cartridges in batches set up in loading plates. These plates are made up of a container and a cover having a number of holes arranged in a rectangular pattern; an equal number of empty primed cartridge cases are first placed in the container, each with its open mouth received in one of the holes of the cover. The assembled loading plate is inserted beneath a powder metering device, which has a number of volumetric metering chambers arranged in the same pattern as the holes of the loading plate, so that one chamber aligns above each empty cartridge case. A powder hopper open at the bottom is wiped across an upper surface of the powder metering device to fill each metering chamber with a charge of powder. The bottoms of the chambers are closed during this filling operation by a perforated slide, which is then opened to permit the powder charges to flow into the waiting cartridge cases beneath.
It sometimes happens that the supply of powder in the hopper is depleted during the filling of a loading plate, and for this or other reasons some of the cartridge cases do not receive a full charge of powder. It is therefore necessary to inspect the powder levels in the cases after the metering operation, and before the cartridges are completed by inserting and crimping bullets. Conventionally, this inspection employs a holding plate having the same number and pattern of holes as the loading plate, and a similar number of probes slidably received in the holes of the holding plate. The loading plate is positioned beneath the holding plate, which is then lowered by a manual crank mechanism to insert the probes into the mouths of the cartridge cases. Each probe which encounters a powder charge is lifted from its seat in the holding plate, to a height which indicates the height of the charge. An operator then visually ascertains whether all of the probes are raised to the same height; if not, the entire batch of cartridges in the charging plate must be rejected and recharged. Careful and continuous attention is required if the assembly of some cartridges with missing or reduced powder charges is to be avoided.